1. Field of the Invention
The present invention relates to a moving image capture apparatus and a moving image capture method. More specifically, the present invention relates to a method for adding a file name to each of a plurality of files, which enables a user to easily recognize content thereof. Furthermore, the present invention relates to a method for appropriately setting an image selectively captured by a user as a thumbnail image.
2. Description of the Related Art
A conventional moving image capture apparatus, such as a video camera, includes an electronic device, such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). Such a conventional moving image capture apparatus outputs visual information captured by an image sensor constituted by the above electronic device, as an image signal. Furthermore, a conventional moving image capture apparatus generates a predetermined data file based on an output image file, and then records the generated data file on a recording unit, such as a hard disk drive (HDD), a digital versatile disc (DVD), or a semiconductor memory.
Visual information captured by such an image sensor is generally a still image. In this regard, a conventional moving image capture apparatus serially records still image signals utilizing a function of general image sensors for generating still images at a rate of several tens of frames per second. Thus, a conventional moving image capture apparatus can record a moving image using the above-described image sensor.
Meanwhile, in recent years, a recording unit has a larger recording capacity than ever because of a rapidly-increasing memory capacity. Here, a conventional moving image capture apparatus displays a list of moving image file identification names (hereinafter simply referred to as a “file name”) on its image display unit, thus allowing a user to confirm data recorded in a recording unit as a file. Thus, a user can operate an operation unit of the moving image capture apparatus to find and select a desired file name.
Generally, a conventional moving image capture apparatus uses, for a file name, a character string that is mechanically generated based on a shooting date and time or a consecutive number. For example, Japanese Patent Application Laid-Open No. 2003-037770 discusses a moving image capture apparatus that extracts character information from an image signal to recognize a character string and sets the thus recognized character string as a file name, thus facilitating managing image files.
Another conventional method automatically extracts a character region from a color image signal acquired from visual information captured by an image sensor. For example, Japanese Patent Application Laid-Open No. 2001-283153 discusses a pattern extraction apparatus that uses a determination unit for determining whether a background color is even and extracts a character string with a high level of accuracy.
Furthermore, Japanese Patent Application Laid-Open No. 09-134406 (corresponding to U.S. Pat. No. 6,035,061) discusses a method for selecting and extracting one file name from among a document, which includes a plurality of character strings. The method discussed in Japanese Patent Application Laid-Open No. 09-134406 (corresponding to U.S. Pat. No. 6,035,061) uses at least one of conditions including a position of a character string, a character string size, whether an underline is added to a character string, whether a frame is added to a character string, and a positional relationship of a character string with another character. Furthermore, the method discussed in Japanese Patent Application Laid-Open No. 09-134406 (corresponding to U.S. Pat. No. 6,035,061) includes a file name extraction unit that assigns a point to a character region in which each character string exists, performs character recognition on a character region having a high point, and sets the recognized character string as a file name.
Meanwhile, a recording capacity of a recording unit has increased because of an increase in a memory capacity, as described above. In this regard, conventional methods have been developed and introduced for allowing a user to easily search for an image file in a case where many moving image files are recorded on a recording medium. For example, a conventional moving image capture apparatus displays, on its image display unit, a list of digest images (hereinafter referred to as “thumbnails”), which can be obtained by compressing one image representing content of a moving image file.
With respect to based on which image in a moving image file a thumbnail is to be generated, Japanese Patent Application Laid-Open No. 11-313316 discusses a method of using an intraframe-coded image that exists at a position later than a first image by a predetermined length of time to generate a thumbnail. However, the moving image capture apparatus discussed in Japanese Patent Application Laid-Open No. 11-313316 cannot assure that the generated thumbnail is one significant image that represents content of a moving image file.
That is, with the moving image capture apparatus discussed in Japanese Patent Application Laid-Open No. 11-313316, the image positioned later than a first image by a predetermined length of time may be an image that does not represent content of a moving image file at all (for example, a solid (black-out) image). Furthermore, in the case of a conventional moving image capture apparatus, an area of a screen of its display unit is limited, and a plurality of thumbnail images is displayed thereon. Accordingly, the size of each thumbnail is restricted to a small size to some extent. Thus, with such a conventional method, it is not easy for a user to recognize content of a moving image file represented by a thumbnail image. Accordingly, it is not easy for a user to correctly select a desired thumbnail image.
In this regard, Japanese Patent Application Laid-Open No. 2005-020351 discusses a video reproduction apparatus that acquires character data from caption information and audio information, as well as from a thumbnail image. The video reproduction apparatus discussed in Japanese Patent Application Laid-Open No. 2005-020351 selects and acquires character data from the acquired caption information and audio information. Furthermore, the video reproduction apparatus discussed in Japanese Patent Application Laid-Open No. 2005-020351 displays the acquired character data together with and at the same time as the selected thumbnail image to allow a user to easily recognize content of a moving image file represented by a thumbnail image.
Moreover, Japanese Patent Application Laid-Open No. 2002-027363 discusses a thumbnail generating apparatus that includes a character recognition unit for analyzing image data and selecting an image having character information and a thumbnail selection unit for generating a thumbnail image based on the image selected by the character recognition unit. The thumbnail generating apparatus discussed in Japanese Patent Application Laid-Open No. 2002-027363 generates a thumbnail based on an image having a character string of a size larger than a predetermined size, thus allowing a user to easily recognize content of a moving image file represented by a thumbnail image.
However, the above-described conventional moving image capture apparatus, such as the apparatus discussed in Japanese Patent Application Laid-Open No. 2003-037770, one character string to be set as a file name cannot be selected from among a plurality of character strings.
The pattern extraction apparatus discussed in Japanese Patent Application Laid-Open No. 2001-283153 extracts a file name of a still image. Accordingly, the pattern extraction apparatus discussed in Japanese Patent Application Laid-Open No. 2001-283153 does not consider time-axis matters, and thus cannot appropriately set a character string that has been intentionally captured by a user at the time of shooting a moving image as a file name.
The digital camera discussed in Japanese Patent Application Laid-Open No. 09-134406 (corresponding to U.S. Pat. No. 6,035,061) captures a series of scenes from a start of shooting to its end as one file, divides the file after the shooting operation has ended, and performs an edition operation for appropriately arranging the divided files. In this case, a conventional method, in dividing one single file into a plurality of files, uses a file name generated in a mechanical manner by adding a consecutive number to a name of the single file. Accordingly, with such a conventional method, a user cannot recognize content of the file based on the file name after the order of the divided files has been arranged. Thus, a user is required to take the trouble of verifying content of each image file.
With the video reproduction apparatus discussed in Japanese Patent Application Laid-Open No. 2005-020351, a user is required to perform processing for appropriately selecting a character string from among a large amount of character data acquired from caption information and audio information separately from processing for selecting a thumbnail image. In order to perform such processing, a user is required to verify a large amount of image data. Thus, with this conventional method, a user is required to perform a complicated operation for generating a thumbnail image.
In the case of the thumbnail generating apparatus discussed in Japanese Patent Application Laid-Open No. 2002-027363, when a character string of a size larger than a predetermined size is included in a plurality of scenes, a plurality of images is generated to serve as an image based on which to generate a thumbnail image. Accordingly, the thumbnail generating apparatus discussed in Japanese Patent Application Laid-Open No. 2002-027363 cannot appropriately set an image selectively captured by a user as a video image representing content of a moving image file as a thumbnail image.